A Randomized, Placebo-Controlled Clinical Trial of Famciclovir in Shelter Cats with Naturally Occurring Upper Respiratory Tract Disease

Upper respiratory tract disease (URTD) is a clinically relevant infectious disease in shelter cats, with individual and population-level welfare implications. The purpose of this study was to evaluate the effectiveness of famciclovir in reducing clinical signs of URTD in shelter cats during a therapeutic period of up to 21 days. Cats at two Northeastern United States animal shelters with URTD clinical signs were enrolled in a pragmatic, prospective, randomized, placebo-controlled clinical trial. Cats received either famciclovir (n = 11, target dose range 40–90 mg/kg) or placebo (n = 11), administered orally twice daily for up to 21 days with once-daily clinical scoring. At enrollment, conjunctival and oropharyngeal samples were collected for respiratory pathogen identification by RT-PCR. Zero-inflated Poisson regression was used to evaluate the treatment group effects and changes in clinical scoring over time. With each day of treatment, cats in both groups were less likely to experience worsening clinical scores; however, the risk of worsening scores with each day of treatment was significantly less in the famciclovir group compared to placebo (p = 0.006). Feline herpesvirus (FHV-1) DNA was detected in 11/21 cats. The findings justify further pragmatic studies to determine whether famciclovir treatment can contribute to a clinically relevant reduction in URTD morbidity in shelter cats.

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Effects of famciclovir in cats with spontaneous acute upper respiratory tract disease

Journal of Feline Medicine and Surgery ◽

10.1177/1098612x19857587 ◽

2019 ◽

Vol 22 (6) ◽

pp. 492-499

Author(s):

Lucy Kopecny ◽

David J Maggs ◽

Christian M Leutenegger ◽

Lynelle R Johnson

Keyword(s):

Respiratory Tract ◽

Clinical Signs ◽

Response To Therapy ◽

Study Entry ◽

Upper Respiratory Tract ◽

Respiratory Tract Disease ◽

Upper Respiratory ◽

Upper Respiratory Tract Disease ◽

Tract Disease ◽

Group D

Objectives The aim of this study was to assess the effects of famciclovir administration in cats with spontaneously acquired acute upper respiratory tract disease. Methods Twenty-four kittens with clinical signs of acute upper respiratory tract disease were randomly allocated to receive doxycycline (5 mg/kg PO q12h) alone (group D; n = 12) or with famciclovir (90 mg/kg PO q12h; group DF; n = 12) for up to 3 weeks. Clinical disease severity was scored at study entry and daily thereafter. Oculo-oropharyngeal swabs collected at study entry and exit were assessed using quantitative PCR for nucleic acids of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), Chlamydia felis, Bordetella bronchiseptica and Mycoplasma felis. Results The median (range) age of cats was 1.5 (1–6) months in group D vs 1.6 (1–5) months in group DF ( P = 0.54). Pathogens detected in oculo-oropharyngeal swabs at study entry included FCV (n = 13/24; 54%), M felis (n = 8/24; 33%), FHV-1 (n = 7/24; 29 %), C felis (n = 7/24; 29%) and B bronchiseptica (n = 3/24; 12%). Median (range) duration of clinical signs was 11.5 (3–21) days in group DF and 11 (3–21) days in group D ( P = 0.75). Median (range) total disease score at the end of the study did not differ between groups (group D 1 [1–1] vs group DF 1 [1–3]; P = 0.08). Conclusions and relevance This study revealed no significant difference in response to therapy between cats treated with doxycycline alone or with famciclovir; cats improved rapidly in both groups. However, identification of FHV-1 DNA was relatively uncommon in this study and clinical trials focused on FHV-1-infected cats are warranted to better evaluate famciclovir efficacy.

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